Buying advice sought re Milling Machines: e.g. Proxxon: FF230 vs. BFW40/E vs. MF70

[John Smith 47Participant @johnsmith47]

Hello

I need advice on what milling machine to buy.

What I'm looking for:
– a compact, high-precision, general purpose table-top milling machine for modelmaking (& general DIY).

– I want to mill & drill holes ranging from 0.5mm to 6??mm (or as large as possible) through metal including mild steel.

– (NOTE: My workshop needs to be cleared away at night so machine needs to be reasonably light…. so max weight say 20Kg?? )

– Budget: £250 to say £1000 inc VAT (absolute max!)

Option A) PROXXON FF 230 MIICRO MILL (474050)
https://www.proxxon.com/en/micromot/24108.php
Power: 140 Watts
Voltage: 230 V
Sprindle RPM: 280rpm to 2,200rpm
Table area: 270 x 80mm (Cross table)
Table travel: 170 x 65mm
Collets: 6, 8 & 10mm
Weight: 17 kg

Cost: £843.18 (incl VAT)

 

Option B) PROXXON MILL/DRILL system on BFW 40/E (7182250)
[BFW 40/E Mill/Drill Motor and Controller +
BFB 2000 Mill/Drill Stand +
KT 150 Compound Table & Step Clamp Set ]
Power: 250 watts
Voltage: 40DCV (secondary)
Sprindle RPM:900-6000rpm "with full torque control"
Collets: x6 from 2.3-6mm :

Table Area: 200 x 200mm.
Table travel: 150 x 150m (Compound Table)
Weight: 15Kg??

Cost: £586.48 (incl VAT)

 

Option C) MICRO miller MF 70
Power: 100 watts (seems rather under-powered)
Voltage: 230 V
Spindle: 5,000 – 20,000rpm (very high speed, but maybe not enough torque for milling?)
Collets: 1.0, 1.5, 2.0, 2.4, 3.0 and 3.2 mm
Table area: 200 x 70mm
Table travel: X:134, Y:46mm
Weight: 7Kg (suspiciously light?)
Cost: £239.65

 

DISCUSSION:
– Option "C)" the Proxxon MF 70, seem suspiciously under-powered & 'suspiciously' cheap. I fear the it won't be able to drill a hole larget than 3.2 mm…

Option B) compared to A):
– Option "B)", the BFW 40/E is faster 6,000 vs 2,000 rpm
– But the collets seem smaller 2.3 to 6MM vs 6 to 10mm
– The table looks more robust
– BUT suspiciously cheaper by £250…
– Also how much of "250 watts" rating will be lost by the transformer?

Here are the images:

A) PROXXON FF 230 milling machine

 

B) PROXON BFW 40/E milling system

 

C) MICRO miller MF 70 milling machine

 

OR some completely different (but good quality) brand?!

I've not done a huge amount of milling before… so all advice is welcome!
Many thanks

J

Edited By John Smith 47 on 29/03/2021 18:01:02

[John Smith 47Participant @johnsmith47]

[Frances IoMParticipant @francesiom58905]

can you use a wheeled stand/table to move it away from living space – those you mention sound more like toy machines not really suited to steel – look at ArcEuro’s offers – milling tends to spread small bits of metal – not usually carpet friendly

Edited By Frances IoM on 29/03/2021 18:13:20

[Andy CarlsonParticipant @andycarlson18141]

The MF70 is fine within its capacity. I use mine for 2mm scale modelling and many other 2mm modellers do too.

It can be converted to use an ER11 spindle but the high minimum speed of the drive is another limitation. I know folks who have addressed that one too, but then you are getting quite far from the original machine. As you know, the axis travel is a further limitation. If you want to drill up to 6mm then I'd say it isn't for you. I can't speak from experience of the other options but rigidity is crucial to a mill so any increase in space for Y or Z travel should also be accompanied by an increase in the bulk of everything that keeps the head positioned with respect to the table.

Trouble is… the price point goes up pretty sharply too.

[JasonBModerator @jasonb]

Sherline would be worth thinking about just inside your weight limit and some very good work has been done on them, of the Proxxon oferings only the FF230 would be anything close to doing what you want

[Andrew TinsleyParticipant @andrewtinsley63637]

Frankly I would not consider a Proxxon mill to be other than a toy. I have seen several of the Proxxon offerings that you mention, they simply are not good enough for working in metal. My own experience of Proxxon tools is they are expensive for what they are and quality isn't very good either.

Jason's mention of Sherline is a much better prospect or the smaller Sieg mills from Arc Eurotrade.

You say you are limited on weight to 20 Kgs. Mills depend on rigidity and that means weight! Your 20 Kg limit means you simply won't get a decent mill for the tasks you wish to use it.

Andrew.

[John HaineParticipant @johnhaine32865]

Andrew is spot on. Avoid Proxxon. Overpriced and under specified.

Edited By John Haine on 29/03/2021 19:48:13

[John Smith 47Participant @johnsmith47]

TBH, as a novice, I'm feeling slighly out of my depth on all this.

Being able to cut mild seel is the entire point of my having a milling machine. But if I can't readily lift the machine off a table, maybe I should bale out now!

SIEG

SIEG – made in China, yes. Their website is awful. (I can't get the Specification tab to work, nor will the video play – not reassuring…)

==> SIEG SX1L Mill on ArcEurTrade.co.uk (150watts) appears to be discontinued
https://www.arceurotrade.co.uk/Catalogue/Machines-Accessories/Milling-Machines/SIEG-SX1L-Mill/SIEG-SX1L-Mill-2

==> SIEG SX1LP HiTorque Mill
https://www.arceurotrade.co.uk/Catalogue/Machines-Accessories/Milling-Machines/SIEG-SX1LP-Mill/SIEG-SX1LP-HiTorque-Mill

Yes, pretty impressive spec, at a good price (£595.00 Inc.VAT) but it's bit of a beast weighing in at 50Kg (61Kg gross). Realistically I'm going to struggle to move that back onto a shelf at night!

Frances – Nope, a wheeled stand isn't an option. Space is tight and it will need to be able to be stored on a shelf.

Andy – Could I drill mild steel at 2mm with a PROXXON MF70? Realistically what do we think the maximum diameter of hole that I should be able to drill mild steel with?

SHERLINE

JasonB – That Sherine 12″ Deluxe Vertical Milling Machine ("our most popular mill&quot["5400 (5410)"] looks like a nice, rather elegant piece of kit. Sensible weight at: 18Kg. The table seems rather narrow at just 70mm deep (but maybe there is a good reason for that??)
Realistically what diametre of hole do you think it could drill through mild steel?

However I am based in the UK, and from what I can see thus far, that looks expensive & difficult/slow to obtain here in the UK.

Either way, what are the reasons why is the Proxxon FF230 better than the Proxxon BFW 40/E?

[Frances IoMParticipant @francesiom58905]

If you need to drill 6mm holes (you don’t state to what depth or accuracy) then it does imply the lump of steel is somewhat larger – that means you need an X-Y table large enough to handle the clamps needed or if you have the money a vice, As pointed out the rigidity depends very much on the weight.

If you stick to aluminium you may be able to get away with a lighter machine. Or as mentioned re 2mm modelling small holes (say 1.5mm or less) can be drilled but the high speeds and small chucks needed are not suitable for 6mm holes

Obviously I’m not aware of your domestic situation but playing around with steel tends to require saws, a large vice to hold the material to be cut etc – and milling, sawing metal etc tends not be compatible with domestic activity, small bits of steel swarf are easily trodden into flooring

A small lathe can do some milling and drilling – many models have been built solely with a lathe as affordable milling machines only came in last 20-30 years – what do you want to make in steel?

Edited By Frances IoM on 29/03/2021 21:42:42

[Andy CarlsonParticipant @andycarlson18141]

Posted by John Smith 47 on 29/03/2021 21:25:40:

TBH, as a novice, I'm feeling slighly out of my depth on all this.

Being able to cut mild seel is the entire point of my having a milling machine. But if I can't readily lift the machine off a table, maybe I should bale out now!

Andy – Could I drill mild steel at 2mm with a PROXXON MF70? Realistically what do we think the maximum diameter of hole that I should be able to drill mild steel with?

I've milled mild steel on the MF70 and would nave no concerns about doing it again. It won't chew metal off at a rate of knots but it will do it. The job needs to be small otherwise it will take ages. Steel swarf from carbide cutters is like thousands of tiny needles so bear that in mind if you plan to do this in a domestic setting.

In terms of drilling I don't think I've ever had a need to drill mild steel on the MF70 because I have other machines. When the MF70 was my only machine I did drill brass and aluminium with 2mm and 3mm holes. It coped with both but the noise was pretty nasty with a 3mm drill. A nice sharp drill and a slower speed machine is a much nicer experience.

3.2mm dia is the maximum the unmodified MF70 will hold. If converted to ER11 then it will go bigger but bigger drills are also longer and the high speed will be even more of an issue.

At the end of the day the MF70 is a small scale modelling machine and this is a model engineering forum so you won't find many folks expressing love for it here but like I said… within its limits (and those limits are small) it is OK.

But honestly, if you want to drill 6mm holes in steel then it's not the machine for the job.

[John Smith 47Participant @johnsmith47]

I do all kinds of random DIY project & innovations, and every project is different.

When I wrote "6??mm" I meant "as wide as possible" for a machine that is reasonably portable (i.e. less than 20Kg or so)

The truth is that for my current project, I'm only needing to drill 2.5mm holes in mild steel. It's just that if I'm really going to spend several hundred GBP, then my thinking is that I may as well get something that will be as broadly useful on other stuff as possible.

For example right now I am cutting quite a lot of 1mm thick mild steel plate. And it would be incredibly useful to be able to do so accurately rather than by hand using a fine hacksaw, followed by a lot of careful filing…

Yes, I would definitely plan to have a vice that can be mounted on the X-Y table.

One of the problem with the Sherline its RPM range does seem VERY slow "70 to 2,800 RPM" (albeit with "Electronically controlled spindle speed range" ) .

TBH, I've never really understood cutting spees.
From what I can see, for drilling holes a 6mm hole in mild steel is about 1,000 RPM
and 2,800 will only take you down to c. 5/32" i.e. 4mm.

I think I saw that you can buy a different pulley set for the Sherline to take the RPM up to 10,000RPM, which from what I cans see would be better for 1mm holes, yes?

[Btw, sorry for newbie question, but the cutting RPM for a drill IS the same as for a milling machine, yes?]

Changing pulley sets seems like a bit of a nuiscance. Obviously question but can't you get milling machines with good gear boxes?

I imaging if you cut too fast the base metal just melts, rather than being cut and it's a mess. And presumably the drill gets too hot and gets bluntened too. But what goes wrong happens if your cutting speeds is too slow?

J

 

Edited By John Smith 47 on 29/03/2021 23:47:11

[JasonBModerator @jasonb]

Have a look through these threads to see what can be done on Sherline machines

Steam Shovel

Log Hauler

Mann Wagon,

UK supplier is Millhill Supplies

Although the machines may not run upto optimum cutting speed they will still be OK with smaller drills so not a game breaker, I regularly drill 0.7mm through steel 3-4mm thick with a machine that has a 2000rpm max.

From the above links you can see a lot can be done with a mill that has a narrow table and you can't expect a big slab of iron and still be able to pick the machine up and put it on a shelf, gearbox will also increase weight. Y travel is almost double the FF230 so greater capacity.

Edited By JasonB on 30/03/2021 07:58:39

Edited By JasonB on 30/03/2021 08:01:26

[Frances IoMParticipant @francesiom58905]

John – there are many books on general workshop techniques which I think will answer many of your questions – 6mm drills I’d run about 200-250 for steel, faster (400 rpm?) for brass. – no way 1000rpm – you don’t melt the metal at high speed merely wreck the drill + the motor driving it.
Milling removes less metal per rev – a 1/4″ (6mm) carbide cutter yes at 1000rpm tho for a high speed steel cutter rather slower

[Andy CarlsonParticipant @andycarlson18141]

Posted by John Smith 47 on 29/03/2021 23:43:44:

I do all kinds of random DIY project & innovations, and every project is different.

It's difficult to predict which jobs will come along but my experience has been that I have not found a need to use the MF70 for domestic projects. My Unimat, Cowells and the Faircut 3 1/2 inch lathe on the other hand have all been put to use in this way. Work has included a new brass button fur our old style doorbell push (maybe 3/4 dia), new buttons for the cooker hood (the old plastic ones disintegrated) and several things with threads on the end to adapt or extend various things.

Whatever machine you have you will find yourself making tooling on the machine, for the machine. I've probably spent more time making tooling than anything else, but with four small lathes and the MF70 that's probably my own fault.

Whatever machine you have you will also find that there are jobs which are too big for it. With 1mm sheet I would expect that Y travel will be a place where you will quickly find the limits. My own experience with small modelling jobs on brass sheet is that I quickly wanted CNC so that I could do accurate diagonals and curves etc. I've done this and it has been successful… but that's a whole other tangent.

I won't attempt to say much more on the subject of spindle speeds. I don't pay a lot of attention to what is 'correct'. I do pay attention to nasty noises. The MF70 speeds are OK for 1mm-3mm carbide milling cutters and drilling 2mm and below. The higher speeds are very handy with sub 1mm drills. Yesterday I was doing 0.3mm holes transversely in 0.5mm brass rod on the MF70…but there are plenty of occasions when I'd like to go lower than 5000 RPM but I can do that on the lathes.

Do consider a lathe but XY travel will not be a strong point there – the usable vertical travel of a milling slide may be less than half of the height of the work mounting face.

[JasonBModerator @jasonb]

Speed will vary a little depending on type of cut and machine but not by a lot. I would be running somewhat faster than Frances.

6mm HSS milling cutter in mild steel 1250-1500rpm, carbide 4-5000rpm or machines max

6mm drill in steel 1250-1500rpm

[John Smith 47Participant @johnsmith47]

JasonB – out of interest, what is your thinking? Why do you run so fast? What are the pros and cons in your experience.

Either way, given that the Sherline only runs at "70 to 2,800 RPM" it doesn't sound like the Sherline would be much use to you.

I mean 70RPM! Why would anyone want to go quite so slowly in any case?

J

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Smith 47 on 30/03/2021 17:00:30:

[…]

I mean 70RPM! Why would anyone want to go quite so slowly in any case?

.

Large diameter slitting saws, fly-cutters, and boring tools spring to mind.

MichaelG.

[Dave HalfordParticipant @davehalford22513]

John,

Perhaps you need to separate the mill from the drill to get what you want.

This at 18kg or something like it from Aldi/Lidl would handle the drilling and the mill can do what it's good at, milling.

[JasonBModerator @jasonb]

Posted by John Smith 47 on 30/03/2021 17:00:30:

JasonB – out of interest, what is your thinking? Why do you run so fast? What are the pros and cons in your experience.

Either way, given that the Sherline only runs at "70 to 2,800 RPM" it doesn't sound like the Sherline would be much use to you.

I mean 70RPM! Why would anyone want to go quite so slowly in any case?

J

I would not say I'm running particularly fast, look at any cutting speed charts and you will see that those rpm figures I gave are mid way between the suggested upper and lower speeds for steel. In old money 100 feet per minute was a good rule of thumb, as you seem to talk in metric then 20-30m per minute would be appropriate.

I don't think there are any cons at running at what the tool is meant to run at, pros are that you won't get premature wear, given the same appropriate chip load then you will be able to feed faster than you would if the cutter was running too slowly which means you get the job done and it's also easier when hand feeding if moving the handwheel at a fair pace to keep it constant than if moving very slowly.

If you want to check the maths then for a 6mm  HSS cutter in mild steel we get

Cutting speed / (Diameter x pi) =rpm

Say 25m/min / (0.006 x 3.142) = rpm

25 / 0,18852 = 1326rpm

So thats mid way between the figures I gave as machine and type of cut will also affect what you can run at to some extent as will depth of cut bot Ae and Ap thats sideways engagement and axial engagement. When I'm milling on the CNC I make use of it's higher 5000rpm to speed and tend to use carbide tooling at the max which is OK on steel but a lot below non ferrous speeds

My manual mill runs 50 -2000 so the added top speed of a Sherline would be useful but as I said earlier if you cant run at the optimum then unless it's ridculously less don't loose sleep over it.

As Michael says there are a number of times a slow speed is useful, countersinking and using hand reamers in the mill are another two points to add If you want another example then lets take a 100mm dia slitting saw instead of a 6mm cutter

25 / (0.1 x 3.142) = 79rpm That is why you want slow speeds too. many an unsuspecting beginner has ruined their first slitting saw by running way too fast!

 

 

Edited By JasonB on 30/03/2021 18:39:28

[John Smith 47Participant @johnsmith47]

Dave Halford –

My thoughts:

1. If I have a milling machine, surely I won't need a separate drill?

2. That said…

+Ves:
Powerful motor: 350w
Nice big chuck: 13mm
Sensible weight: 18Kg

-Ves:
Speed: 600-2600RPM is a bit slow for small drilling.
Cost: £86.64(suspiciously cheap!)

I'm sure it's a BAD idea, but what would actually happen if I tried to mill (i.e. cut horizontally with it?)

From looking at it, I suppose the main shaft will flex a bit, making it inaccurate. And maybe the bearings aren't designed to cope with lateral forces… But at least it's got a reasonably powerful motor (350w), and it's not too heavy (18Kg)

JasonB – thank you (genuinely) for the lesson on cutting speeds… esp. in metric. In the past I have ducked the issue but going forwards, I shall use that!

That said, I just looked up the cutting speed for mild steel is quoted as: "3–38 meters per minute".
So for 6mm – which is the probably the largest diameter I would hope to cut – we have:

3m/min ==> 159 rpm
38m/min ==> 2,016 rpm

…which seems like an incredibly wide range!

But "with coolant" it's "6–7 m/min" ==> c 345 RPM
[Btw, does this mean when cutting slower coolant is more important?]

I also looked up the cutting speed for aluminium "122-305" m/min
122 m/min ==> 6,472 rpm
304m/min ==> 16,181 rpm

Stainless Steel (300 & 400 series) cutting speed: "23–40" m/min
23 m/min ==> 1,220 rpm
40 m/min ==> 2,122 rpm

Polyethylene cutting speed:
"12" m/min ==> 637rpm

Conclusion:
I don't think I'm going to use anything less than 600 rpm, but form smaller stuff (e.g. 1mm cuts), I really need at least 10,000 rpm.

WHERE I'VE GOT TO (so far)

1. BRANDS
1.1. PROXXON
Proxxon clearly has its detractors & haters(!) but having bought one I think the quality is OK-ish, even if it is painfully over-priced. Either way I've not seen much else for very small (i.e. very high RPM) work.
– The MF 70 is fast 5,000 to 20,000 rpm a but a bit of a toy (very, very small cuts only)
– The FF 230 is a reasonable weight (17Kg) but too slow (up to 2200rpm)
– The FF 500/BL is stupidly expensive (£1,808.15)
– Personally I don't mind Proxxon, but would prefer not.

1.2. SHERLINE
Quality looks very good, but hard to buy here in the UK.
RPM is very slow "70 to 2800 RPM"
Motor also looks rather weak ("60 watts power output)

1.3. SEIG
– X0 Digital Micro Mill (14Kg, 150Watts, "0 to 5,000" RPM) ==> but discontinued
– SX1LP "HiTorque Mill" (50Kg, 250Watts, "100-5000 rpm) ==> 50Kg is too heavy

4. WEIGHT
I was hoping to find a milling machine that is half way between the 7kg Proxxon MF 70 and the 50Kg SIEG X1LP.
Maybe spec-wise 20KG is unrealistic, but I'm never going to lift a 50Kg machine on and off a shelf very day.
==> Compromise 30Kg?

3. SPEEDS
I was hoping to find a milling machine that can do both very fine work and "as large diameters as is reasonable for the weight".

Running the numbers, cutting mild steel 1mm at 25m/min ==> 8,000 rpm
Although to be realistic 6mm may be pushing it, as JasonB has pointed out, for 6mm diameter cutting reasonable speed would be 1320rpm. Given that I'm going to want to cut plastic (slower cutting ) and aluminium (faster cutting)

So on balance I now think a reasonable target RPM range would be 600 to 10,000 rpm

MY CONCLUSION (so far)
– I need a machine that is designed to do milling
– Weight up to 30Kg if necessary, definitely not 50Kg
– Speed range: 600 to 10,0000 rpm

Does such a machine exist? Maybe the Sherline – if I can acquire one here in the UK – but with the conversion kit

J

[John HaineParticipant @johnhaine32865]

Have you looked at the Taig machines, sold by Peatol in the UK? I've seen a CNC conversion in action at a couple of exhibitions and it looks pretty good to me.

[Pete.Participant @pete-2]

It's only 4 screws holding the column of the sieg x1 to the base? Would it be too time consuming to separate into two halves to be put away?

Edited By Pete. on 31/03/2021 16:57:51

[SillyOldDufferModerator @sillyoldduffer]

Posted by John Smith 47 on 31/03/2021 15:44:12:

D

…

MY CONCLUSION (so far)
– I need a machine that is designed to do milling
– Weight up to 30Kg if necessary, definitely not 50Kg
– Speed range: 600 to 10,0000 rpm

Does such a machine exist? …

I fear the answer is no! It's a really tough requirement because the machine needs to be lightweight AND high-speed AND powerful AND able to handle milling stresses. The limited budget doesn't help either.

Might be more practical to meet the requirement with two different tools, a high-speed drill plus a small milling machine within the weight limit. Or to accept the compromise imposed on drilling by a slowish mill.

Using a drill as a mill isn't an option: trust me, everyone since Adam has wondered if might be OK! If drills worked as mills we'd all be doing it. Sadly, drills just aren't rigid enough to take milling forces. Poor results and dangerous to the operator.

Speed isn't the only criteria: the power / torque needed to cut metal is proportional to the area under the cut, so a 6mm drill needs about 9 times more power than a 1mm, which suggests trying to combine high-rpm drilling and low-rpm milling in one machine is mechanically tricky. For that reason a specialist high-speed drill for small diameters will work well with a dinky motor and modest bearings hopeless for milling. And the power and bearings of a milling machine don't favour high speed. High-speed and high power at the same time exist in CNC world, but are well outside the budget.

Although small drills like to be run at high-speed, they work fairly well at 2800rpm, so a mill might be good enough. It depends on what you're doing and how much of it. Cheap poorly ground drills perform badly at low speed, and low speed is always a problem drilling hard materials like PCBs.

May not be relevant, but the slow speed of a mill can be used to make holes much wider than 6mm in steel. Providing a hole big enough to take a boring bar can be made first, hole diameter is only limited by the size of the table.

If I knew of a good answer I'd share it. Perhaps someone else knows of a suitable machine?

Dave

 

Edited By SillyOldDuffer on 31/03/2021 17:09:25

[John HaineParticipant @johnhaine32865]

Because of the hours you put in inserting little bits of packing to tram the head to the table….

[Frances IoMParticipant @francesiom58905]

Mike Cox described a mod to the SX1 mill that removed the tilting head and locked the head to a vertical guide – the head and guide are held by 4 bolts – if a dowel or two were added to lock the the position then possibly sufficient accuracy could be obtained for most applications leaving tramming for when the highest accuracy is needed – just an idea as splitting this way makes the two sections relatively easy to handle – a tramming device based on 2 DTIs mounted on a bar would make tramming a somewhat faster operation.

Just putting the idea out ? – I havn’t tried it but I did have to separate the head + column from the table to move my SX1LP into my cellar workshop accessed by a somewhat awkward staircase -it was a few years ago but given my age I suspect others could handle a similar machine this way.

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